Design of Class E Resonant Rectifiers and Diode Evaluation for VHF Power Conversion

Resonant rectifiers have important applications in very-high-frequency (VHF) power conversion systems, including dc-dc converters, wireless power transfer systems, and energy recovery circuits for radio-frequency systems. In many of these applications, it is desirable for the rectifier to appear as a resistor at its ac input port. However, for a given dc output voltage, the input impedance of a resonant rectifier varies in magnitude and phase as output power changes. This paper presents a design methodology for class E rectifiers that maintain near-resistive input impedance along with the experimental demonstration of this approach. Resonant rectifiers operating at 30 MHz over 10:1 and 2:1 power ranges are used to validate the design methodology and identify its limits. Furthermore, a number of Si Schottky diodes are experimentally evaluated for VHF rectification and categorized based on performance.